So Now There Are 7,000 Methane Bubbles Beneath Siberia

Yamal Crater - an example of what happens when one of these methane pockets explodes. Siberian Times via YouTube

By Robin Andrews

21 Mar 2017, 21:17

Back in 2016, Siberia’s amusingly named Bely Island made headlines around the world after sections of its grassy landscape became somewhat bouncy.

As it turned out, the island was leaking greenhouse gases at a seemingly remarkable rate. In fact, the air escaping from the ground there contained 100 times more methane and 25 times more carbon dioxide – the two most potent greenhouse gases by far – than the surrounding atmosphere.

This time last year, just 15 of these near-surface, water-coated methane bubbles had been identified. Now, as reported by the Siberian Times, there are 7,000 of them. It's not clear how this number was achieved, and how accurate it is, but if it is true, then it's certain not good news.

Thanks to the omnipresence of bacterial and archaeal life within its soil, there’s a heck of a lot of methane and carbon dioxide locked up within Siberia’s permafrost. When conditions are warm enough, they thoroughly enjoy breaking down the plant and animal life trapped there, and they give off the two aforementioned greenhouse gases as a waste product.

Permafrost, as the name implies, is meant to be somewhat permanent – it’s a mixture of ice and soil, buried just beneath the surface, that remains frosted over for at least two years or more. However, thanks to the rapid pace of climate change, the region is warming incredibly fast – sometimes twice as fast as the rest of the planet.

When permafrost melts, the organic matter begins to decay, and methane and carbon dioxide within it is released. Although carbon dioxide lasts longer in the atmosphere than methane, the latter gas is actually around 28-36 times more potent at trapping heat in the long-term, which makes it fairly dangerous when it comes to global warming.

Under low-oxygen conditions, the microbes there tend to break the organic carbon into methane. Its continued, rapid release – as documented quite extravagantly by these underground bubbles – may be able to warm the planet rapidly, if there’s enough of it there, and the thawing is severe and widespread enough.

A suddenly warmer planet means not only melting ice caps and expanding seas, but less stable stores of permafrost worldwide. This means that the world is potentially slipping into a self-reinforcing cycle of heating and methane release. Importantly, it’s not clear where the point of no return may be, and scientists are somewhat unsure how much of this methane would actually make it into the atmosphere.

The Russian tundra isn’t the only place where methane is stored in this way. In fact, there’s probably a lot more hiding deep beneath the oceans. Earlier this month, scientists announced that they found a record-breaking pool of it within the seabed of the Pacific Ocean, stretching all the way from Guatemala to Hawaii.

As the surface world warms, the oceans take on more carbon dioxide. This makes them more acidic, which can erode away at the sedimentary cap on these submarine methane reserves, which allows them to degas and escape into the atmosphere. Once again, the world could tip towards that dangerous self-reinforcing cycle, although it's again not clear how much methane is leaking out, and how much is reaching the atmosphere.

In any case, although peer-reviewed data is as yet forthcoming, these bouncy patches of grass in Siberia look to be a genuinely worrying sign of things to come.